Structural vibrations frequently need to be suppressed or “damped” to prevent damage to a structure. To accomplish this, one standard practice is to use a tuned damper. Tuned dampers are devices that are intentionally designed to have the same natural frequency as the structure they are damping. During vibration, the motion of the tuned damper dissipates energy and reduces primary structural vibration. The standard practice typically uses elastomerically-suspended moving masses or linear dampers that consist of a piston housed in a fluid-filled cylinder that is attached to a moving mass. Energy is dissipated by motion of the fluid in the cylinder or through strain of the elastomeric material. The magnitude of the energy that can be dissipated by a tuned damper is proportional to the magnitude of the mass or the square of the distance that the moving mass travels. In either of these standard practices, the range of motion of the moving mass is restricted. For example, if the damper's piston has to be capable of 2 inches of movement in either direction, the internal length of the fluid-filled cylinder would have to be at least 4 inches while the connecting rod must also be at least 4 inches to span the piston's travel. Additionally, the rod connections, cylinder walls, and piston all have thickness. This means that the overall length of the linear damper is about 9 inches to achieve +/−2 inches of damping movement. Unfortunately, not all applications have the space to accommodate the size requirements of a linear damper or can tolerate the weight penalty of a smaller device.
In the case of masses suspended using elastomeric materials (i.e., those whose material strain exhibits a viscous force), the allowable range of motion is severely restricted by the allowable strain of the elastomeric material.